The present invention relates to suspension systems and more particularly to an actuator apparatus for controlling a valve mechanism of a suspension system that includes a valve actuating assembly operable between at least two rider-selectable positions and an adjuster assembly for adjusting the damping characteristics of at least one of the rider-selectable positions.
Typically, a suspension system includes a piston disposed in a cylinder of housing for reciprocation therein. The piston divides the cylinder into two opposed chambers. A piston shaft is connected to the piston and extends from the piston to a position outside of the cylinder. A fluid, such as oil, or air, or the like, is normally contained in the chambers. In use, the fluid passes between the chambers in response to reciprocation of the piston in the cylinder to affect damping.
The damping characteristics of a suspension system can affect the quality of performance provided by a shock absorber for a given application. Damping characteristics are affected by various factors such as rider weight, rider skill, terrain conditions, etc. Accordingly, it is desirable to provide a suspension system wherein the damping characteristics are adjustable. Further, it is advantageous to provide shock absorbers that are externally adjustable by the rider.
A typical design for a damping adjuster uses an adjuster rod that extends down the center of the piston shaft and engages the valve mechanism or performs the function of the valve mechanism. Adjustment is commonly made in either of two ways, the adjuster rod is moved axially (up or down) to alter damping or the adjuster rod is rotated to alter damping. For example, a cam attached to a lever may be engageable with the adjuster rod to vary the axial position of the rod. One problem associated with this configuration is that any given angular position of the lever/cam corresponds to exactly one position of the adjuster rod. This limits the ability of the rider to customize the damping characteristics of the suspension system to suit the terrain or the rider's particular riding style.